Induction motor having full pitch winding

ABSTRACT

A blower motor is provided for use in a machine. The motor includes a stator and a rotor rotatable about an axis. The stator includes a generally toroidal core, a first-main winding, and an auxiliary winding that is electrically out of phase with the first-main winding. The first-main winding and the auxiliary winding are both full pitch windings.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/629,276, filed Feb. 23, 2015, the entire disclosure of whichis hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to an electric motor including astator and a rotor. The stator includes a core and a winding wound aboutthe core.

2. Discussion of the Prior Art

Electric motors are conventionally used in a variety of applications.For instance, an electric motor may be provided in the form of a blowermotor for use in a heating, ventilation, and air conditioning (HVAC)system.

Electric motors conventionally include a stator core and at least onewinding wound about the core. Winding harmonics often result in noisethat, in certain circumstances (e.g., use of a blower motor in an HVACapplication), is highly undesirable.

SUMMARY

According to one aspect of the present invention, a blower motor isprovided for use in a machine. The motor comprises a stator and a rotorrotatable about an axis. The stator includes a generally toroidal coreincluding a plurality of arcuately spaced apart teeth, and a first-mainwinding. Each pair of adjacent teeth defines a slot therebetween. Thefirst-main winding includes a plurality of first-main first coils woundabout the core. Each of the first-main first coils includes a pair ofarcuately spaced apart, generally axially extending first-main primaryslot portions. Each of the pairs of first-main primary slot portionsdefines a pair of arcuately spaced apart outermost margins of thecorresponding first-main first coil. The first-main winding generates aplurality of first-main poles at respective arcuately spaced apartfirst-main pole locations. The motor has a slot to pole ratio of 6 to 1.The slots include a plurality of first-main pole-location slots. Thefirst-main winding is a full pitch winding, with corresponding pairs ofsaid first-main primary slot portions and said first-main pole locationsbeing positioned within respective ones of the first-main pole-locationslots.

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are further described below in thedetailed description of the preferred embodiments. This summary is notintended to identify key features or essential features of the claimedsubject matter, nor is it intended to be used to limit the scope of theclaimed subject matter.

Various other aspects and advantages of the present invention will beapparent from the following detailed description of the preferredembodiments and the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Preferred embodiments of the present invention are described in detailbelow with reference to the attached drawing figures, wherein:

FIG. 1 is a front perspective view of a blower motor constructed inaccordance with a preferred embodiment of the present invention, withthe motor being depicted in combination with a blower assembly, which isshown only schematically;

FIG. 2 is a front perspective view of the motor of FIG. 1, with theblower assembly removed;

FIG. 3 is a front perspective view of the motor of FIGS. 1 and 2, withthe shell, front endshield, and blower assembly removed;

FIG. 4A is a schematic front view of the stator core and windings of themotor of FIGS. 1-3, with the auxiliary winding energized;

FIG. 4B is a schematic front view of the stator core and windings of themotor of FIGS. 1-3, with the first-main winding energized; and

FIG. 4C is a schematic front view of the stator core and windings of themotor of FIGS. 1-3, with the second-main winding energized.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the preferred embodiments.

Furthermore, directional references (e.g., top, bottom, front, back,side, etc.) are used herein solely for the sake of convenience andshould be understood only in relation to each other. For instance, acomponent might in practice be oriented such that faces referred to as“top” and “bottom” are sideways, angled, inverted, etc. relative to thechosen frame of reference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is susceptible of embodiment in many differentforms. While the drawings illustrate, and the specification describes,certain preferred embodiments of the invention, it is to be understoodthat such disclosure is by way of example only. There is no intent tolimit the principles of the present invention to the particulardisclosed embodiments.

With initial reference to FIGS. 1-3, a motor 10 is provided. The motor10 includes a stator 12 and a rotor 14. The rotor 14 is rotatable aboutan axis.

As will be described in greater detail below, the motor 10 is preferablya permanent-split capacitor (PSC) induction motor. It is permissibleaccording to some aspects of the present invention, however, for themotor to be of another type. For instance, the motor might alternativelybe a capacitor start motor or a resistance start motor.

The motor 10 is preferably a single-phase motor, although it ispermissible according to some aspects of the present invention for themotor to be a multi-phase motor.

The motor 10 is preferably a blower motor for use in an HVAC system.More particularly, as shown in FIG. 1, the motor 10 is preferablyprovided in combination with a blower assembly 15. The blower assembly15 preferably includes a housing 15 a and a blower wheel 15 b includinga plurality of vanes 15 c. It is permissible, however, for the motor tobe a blower motor for use in an alternative application.

In a preferred embodiment, as illustrated, the stator 12 at leastsubstantially circumscribes the rotor 14, such that the motor 10 is aninner rotor motor. It is permissible according to some aspects of thepresent invention, however, for the motor to instead be an outer rotormotor (i.e., for the rotor to at least substantially circumscribe thestator).

Preferably, a circumferentially extending radial gap (not shown) isdefined between the stator 12 and the rotor 14.

The motor 10 further preferably includes a housing 16 including a shell18 and front and rear endshields 20 and 22, respectively.

The housing 16 preferably defines a motor chamber 24 that at leastsubstantially receives the stator 12 and the rotor 14.

The endshields 20 and 22 preferably support the stator 12 by means of aplurality of fasteners (not shown).

The shell 18 is preferably at least substantially cylindrical in form tocircumscribe the stator 12. However, it is permissible according to someaspects of the present invention for the shell to be alternativelyshaped. For instance, the shell could be generally cuboidal in form orinclude a pair of flat sides interconnected by a pair of arcuatelyextending sides. Furthermore, the shell could alternatively extend onlypart of the way around the stator.

In a preferred embodiment, axially spaced apart front and rearpluralities of ventilation openings 26 and 28, respectively, are formedin the shell 18. The front ventilation openings 26 are preferably evenlyarcuately spaced apart, while the rear ventilation openings 28 arelikewise preferably evenly arcuately spaced apart. It is permissibleaccording to some aspects of the present invention, however, for theshell to be at least substantially devoid of openings therethrough orfor the ventilation openings to be alternatively configured (e.g.,unevenly spaced or provided only at the front of the shell).

The front endshield 20 is preferably at least substantially devoid ofopenings therethrough. The rear endshield 22, however, preferablydefines a plurality of ventilation slots 30 therethrough. The frontendshield may alternatively include openings therethrough, however,and/or the rear endshield may be at least substantially devoid ofopenings.

In a preferred embodiment, the rotor 14 includes a rotor core 32 and aplurality of conductive bars (not shown). More particularly, the rotorcore 32 preferably includes a yoke 34 and a plurality of arcuatelyspaced apart rotor teeth (not shown) extending generally radiallyoutwardly from the yoke 34.

The rotor teeth preferably define a plurality of slots (not shown)therebetween. The conductive bars preferably extend throughcorresponding ones of the slots.

The slots and, in turn, the conductive bars, may be either skewed(angled) relative to the rotor axis or parallel therewith withoutdeparting from the scope of the present invention.

The rotor 14 further preferably includes a front end ring 36 and a rearend ring (not shown). The conductive bars preferably extend between andinterconnect the front end ring 36 and the rear end ring.

In a preferred embodiment, the front end ring 36 includes a plurality ofintegrally formed front blades 40, such that the front end ring 36 actsas a fan upon rotation of the rotor 14. The rear end ring is preferablysimilarly provided with integrally formed rear blades (not shown). It ispermissible according to some aspects of the present invention, however,for the front and/or rear blades to be non-integrally formed.Furthermore, the front and/or rear blades may be omitted entirely.

In a preferred embodiment, the rotor core 32 comprises a plurality ofcircumferentially continuous rotor laminations (not shown). It ispermissible according to some aspects of the present invention, however,for the rotor core to be non-laminated and/or circumferentiallydiscontinuous. For instance, the rotor core might be monolithicallyformed or comprise a plurality of discrete, interconnected laminated ornon-laminated arcuate segments.

In a preferred embodiment, the rotor 14 further includes a rotatableshaft 42.

The rotor 14 is preferably rotatably supported relative to the front andrear endshields 20 and 22, respectively, by means of a front bearing 44and a rear bearing (not shown).

In a preferred embodiment, the stator 12 includes a generally toroidalstator core 46 and a plurality of windings 48, 50, and 52 wound aboutthe core. The windings 48, 50, and 52 are shown schematically in a firstform in FIG. 3 and in a more detailed schematic form in FIGS. 4A-4C,which provide a wiring diagram for the motor 10. The windings 48, 50,and 52 will be discussed in greater detail below.

The stator core 46 may be electrically insulated (e.g., by means ofinsulative overmolding, paper, and/or powder coating) or non-insulatedwithout departing from the scope of the present invention.

The stator core 46 preferably includes a yoke 54 and a plurality ofarcuately spaced apart teeth 56 extending generally radially inwardlyfrom the yoke 54. Each pair of adjacent teeth 56 preferably defines aslot 58 therebetween.

More particularly, as illustrated schematically in FIGS. 4A-4C, thestator core 46 preferably including thirty-six (36) teeth 56 (enumerated1 to 36 in FIGS. 4A-4C) defining thirty-six (36) slots 58.

As discussed in greater detail below, the motor 10 preferably has aplurality of poles P. Most preferably, the motor 10 has six (6) poles P,such that the motor 10 is a thirty-six (36) slot, six (6) pole motor.The motor 10 thus preferably has a six (6) to one (1) slot:pole ratio.It is permissible according to some aspects of the present invention,however, for the numbers of slots and/or poles to vary from thepreferred numbers presented above. For instance, in accordance with thepreferred slot:pole ratio, the motor might alternatively haveforty-eight (48) slots and eight (8) poles.

In a preferred embodiment and as shown schematically in FIGS. 4A-4C, thewindings 48, 50, and 52 are an auxiliary winding 48, a first-mainwinding 50, and a second-main winding 52. Provision of two (2) mainwindings 50 and 52 preferably enables operation of the motor 10 at two(2) different speeds. More or fewer windings may be provided withoutdeparting from some aspects of the present invention, however. Forinstance, only one main winding might be provided, or the auxiliarywinding might be omitted.

In a preferred embodiment and as illustrated schematically in FIGS.4A-4C, the auxiliary winding 48 is electrically out of phase with thefirst-main winding 50 and the second-main winding 52. More particularly,the auxiliary winding 48 is preferably ninety (90) electrical degreesout of phase with the first-main winding 50 and the second-main winding52, with the first-main winding 50 and the second-main winding 52 beingelectrically in phase with each other. It is permissible according tosome aspects of the present invention, however, for the auxiliarywinding to be out of phase with either or both of the first andsecond-main windings to a greater or lesser extent, for the auxiliarywinding to be in phase with one or both of the first and second-mainwindings, and/or for the first and second-main windings to beelectrically out of phase with each other.

As will be discussed in greater detail below, each of the windings 48,50, and 52 is preferably a full pitch winding.

Each of the windings 48, 50, and 52 is preferably formed of acorresponding wire 48 a, 50 a, or 52 a. The wires 48 a, 50 a, and 52 aeach preferably comprise one or more electrically conductive materialssuch as copper or aluminum.

The wires 48 a, 50 a, and 52 a are each preferably interconnected, suchthat the auxiliary winding 48, the first-main winding 50, and thesecond-main winding 52 are all electrically interconnected. Furthermore,a speed tap may be provided at each connection location. It ispermissible, however, for one or more of the wires to be disconnectedfrom the others without departing from the scope of the presentinvention and/or for more or fewer speed taps to be provided. Forinstance, in an alternative embodiment, the wire ends might be insulatedand no speed taps provided.

As noted previously, FIGS. 4A-4C are schematic winding diagrams for themotor 10. More particularly, FIG. 4A is a schematic winding diagramillustrating the motor 10 when the auxiliary winding 48 is energized.FIG. 4B is a schematic winding diagram illustrating the motor 10 whenthe first-main winding 50 is energized. FIG. 4C is a schematic windingdiagram illustrating the motor 10 when the second-main winding 52 isenergized. As will be discussed in greater detail below, in keeping withthe preferred induction motor configuration, whichever winding of thewindings 48, 50, and 52 is energized preferably defines or generates theaforementioned poles P at respective arcuately spaced apart polelocations.

More particularly, with initial reference to FIG. 4A, the auxiliarywinding 48 preferably includes a plurality of auxiliary first coils 60wound about the stator core 46 and a plurality of auxiliary second coils62 wound about the stator core 46. The auxiliary second coils 62 arepreferably alternately arcuately arranged with the auxiliary first coils60.

The auxiliary winding 48 preferably includes three (3) of the auxiliaryfirst coils 60 and three (3) of the auxiliary second coils 62, althoughit is permissible according to some aspects of the present invention fordifferent numbers of auxiliary first and/or second coils to be provided.

In a preferred embodiment, each of the auxiliary first coils 60 includesa plurality of auxiliary first slot portions 64 each extending through acorresponding one of the slots 58. (As discussed in greater detailbelow, a slot portion as referred to herein comprises the portion orportions of the associated wire that extend through a given one of theslots. For instance, an auxiliary first slot portion 64 comprises theportion(s) of the wire 48 a that extend through the corresponding slot58.)

The auxiliary first slot portions 64 of each of the auxiliary firstcoils 60 preferably include a pair of arcuately spaced apart, generallyaxially extending auxiliary primary slot portions 66. The location ofeach pole P preferably coincides with a corresponding one of theauxiliary primary slot portions 66 when the auxiliary winding 48 isenergized, such that the auxiliary winding 48 is a full pitch winding.That is, the poles P are located at selected ones of the slots 58 ratherthan, for instance, on selected ones of the teeth 56.

More particularly, each of the auxiliary first coils 60 preferablyincludes a plurality of interconnected auxiliary first loops includingan auxiliary innermost first loop 68, an auxiliary intermediate firstloop 70, and an auxiliary outermost first loop 72. The auxiliaryoutermost first loop 72 preferably at least substantially circumscribesthe auxiliary innermost first loops 68. The auxiliary intermediate firstloop 70 is preferably positioned between the auxiliary innermost firstloops 68 and the auxiliary outermost first loop 72.

Each auxiliary first loop 68, 70, and 72 preferably comprises aplurality of turns of the wire 48 a. (As used herein, the number ofturns of a wire is the number of times the wire wraps around acorresponding tooth or teeth). In a low horsepower motor, for instance,each loop might comprise three (3) turns of the wire, while each loopmight comprise hundreds of turns of the wire in a high horsepower motor.

Each of the auxiliary innermost first loops 68 preferably includes apair of arcuately spaced apart, generally axially extending auxiliaryinnermost first slot portions 74 extending through corresponding ones ofthe slots 58. Similarly, each of the auxiliary intermediate first loops70 preferably includes a pair of arcuately spaced apart, generallyaxially extending auxiliary intermediate first slot portions 76extending through corresponding ones of the slots 58. Likewise, each ofthe auxiliary outermost first loops 72 preferably includes a pair ofarcuately spaced apart, generally axially extending auxiliary outermostfirst slot portions 78 extending through corresponding ones of the slots58.

Preferably, the auxiliary innermost, intermediate, and outermost firstslot portions 74, 76, and 78, respectively, all extend through differentones of the slots 58. More particularly, in a preferred embodiment, theauxiliary innermost, intermediate, and outermost first loops 68, 70, and72 of each of the auxiliary first coils 60 are concentric andrespectively circumscribe two (2), four (4), and six (6) of the teeth56. For instance, in the preferred embodiment shown schematically inFIG. 4A and others, the auxiliary innermost first loops 68 of a selectedone of the auxiliary first coils 60 circumscribes teeth 3-4. Theauxiliary intermediate first loop 70 of the same one of the auxiliaryfirst coils 60 circumscribes teeth 2-3-4-5. The auxiliary outermostfirst loop 72 of the same one of the auxiliary first coils 60circumscribes teeth 1-2-3-4-5-6.

In a preferred embodiment, as shown in FIG. 4A, the locations of thepoles P when the auxiliary winding 48 is energized preferably correspondwith respective ones of the auxiliary outermost first slot portions 78,such that the auxiliary outermost first slot portions 78 are theauxiliary primary slot portions 66. That is, each of the pairs ofauxiliary primary slot portions 66 defines a pair of arcuately spacedapart outermost margins of the corresponding auxiliary first coil 60.

In a preferred embodiment, each of the auxiliary second coils 62includes a pair of interconnected auxiliary second loops including anauxiliary innermost second loop 80 and an auxiliary outermost secondloop 82. The auxiliary outermost second loop 82 preferably at leastsubstantially circumscribes the auxiliary innermost second loop 80.

Similar to the auxiliary first loops 68, 70, and 72 of the auxiliaryfirst coils 60, each auxiliary second loop 80 and 82 of the auxiliarysecond coils 62 preferably comprises a plurality of turns of the wire 48a.

In a preferred embodiment, each of the auxiliary second coils 62includes a plurality of auxiliary second slot portions 84 each extendingthrough a corresponding one of the slots 58. More particularly, each ofthe auxiliary innermost second loops 80 preferably includes a pair ofarcuately spaced apart, generally axially extending auxiliary innermostsecond slot portions 86 extending through corresponding ones of theslots 58. Likewise, each of the auxiliary outermost second loops 82preferably includes a pair of arcuately spaced apart, generally axiallyextending auxiliary outermost second slot portions 88 extending throughcorresponding ones of the slots 58.

Preferably, the auxiliary innermost and outermost second slot portions86 and 88, respectively, all extend through different ones of the slots58. More particularly, in a preferred embodiment, the auxiliaryinnermost and outermost second loops 80 and 82 of each of the auxiliarysecond coils 62 are concentric and respectively circumscribe two (2) andfour (4) of the teeth 56. For instance, in the preferred embodimentshown schematically in FIG. 4A and others, the auxiliary innermostsecond loop 80 of a selected one of the auxiliary second coils 62circumscribes teeth 9-10. The auxiliary outermost second loop 82 of thesame one of the auxiliary second coils 62 extends around teeth8-9-10-11.

Furthermore, the auxiliary primary slot portions 66 preferably extendthrough different ones of the slots 58 than any of the auxiliary secondslot portions 84 (i.e., the auxiliary innermost and outermost secondslot portions 86 and 88, respectively), such that the poles P are spacedfrom the auxiliary second slot portions 84 when the auxiliary winding 48is energized.

Yet further, in keeping with the preferred arcuately alternatingarrangement of the auxiliary first and second coils 60 and 62,respectively, it is preferred that the auxiliary first slot portions 64(including the auxiliary innermost, intermediate, and outermost firstslot portions 74, 76, and 78, respectively) and the auxiliary secondslot portions 84 (including the auxiliary innermost and outermost secondslot portions 86 and 88, respectively) all extend through different onesof the slots 58.

Such a preferred arrangement is particularly conducive toward efficientwinding of the auxiliary first and second coils 60 and 62, asinterference with already-wound slot portions is avoided as windingprogresses. It is permissible according to some aspects of the presentinvention, however, for an alternative winding layout to be used inwhich at least some of the slots are shared.

For instance, rather than including three (3) auxiliary first coils andthree (3) auxiliary second coils, the auxiliary winding mightalternatively include six at least substantially identical coils, eachincluding an innermost loop circumscribing two (2) teeth and presentinga pair of innermost slot portions, an intermediate loop circumscribingfour (4) teeth and presenting a pair of intermediate slot portions, andan outermost loop circumscribing (6) teeth and presenting a pair ofoutermost slot portions. In such an alternative embodiment, assuming thepreferred thirty-six (36) tooth, thirty-six (36) slot stator coreconfiguration is retained, each outermost slot portion will extendthrough the same slot as one of the outermost slot portions of anadjacent one of the coils.

It is particularly noted, however, that the above-described alternativeuniform coil embodiment retains the essence of the pole positioningprinciples of the preferred embodiment. That is, each pole in thealternative uniform coil embodiment is located at one of the slots so asto coincide with a slot portion. More particularly, each pole in thealternative uniform coil embodiment is located at one of the sharedslots so as to coincide with a pair of outermost slot portions eachassociated with a different one of a pair of adjacent coils.

In a preferred embodiment, the first-main winding 50 is configuredsimilarly to the auxiliary winding 48. More particularly, as shown inFIGS. 4A-4C, the first-main winding 50 is preferably configuredidentically to the auxiliary winding 48 except for being rotatedrelative the auxiliary winding 48 by ninety (90) electrical degrees andbeing positioned radially inwardly relative to the auxiliary winding 48.

Therefore, for the sake of brevity and clarity, redundant descriptions,particularly of permissible variations to the preferred windingconfigurations, will be generally avoided here. Unless otherwisespecified, the detailed descriptions of the auxiliary winding 48 shouldtherefore be understood to apply at least generally to the first-mainwinding 50, as well.

With particular reference to FIG. 4B, the first-main winding 50preferably includes a plurality of first-main first coils 90 wound aboutthe stator core 46 and a plurality of first-main second coils 92 woundabout the stator core 46. The first-main second coils 92 are preferablyalternately arcuately arranged with the first-main first coils 90.

The first-main winding 50 preferably includes three (3) of thefirst-main first coils 90 and three (3) of the first-main second coils92.

In a preferred embodiment, each of the first-main first coils 90includes a plurality of first-main first slot portions 94 each extendingthrough a corresponding one of the slots 58.

The first-main first slot portions 94 of each of the first-main firstcoils 90 preferably include a pair of arcuately spaced apart, generallyaxially extending first-main primary slot portions 96. The location ofeach pole P preferably coincides with a corresponding one of thefirst-main primary slot portions 96 when the first-main winding 50 isenergized, such that the first-main winding 50 is a full pitch winding.That is, the poles P are located at selected ones of the slots 58 ratherthan, for instance, on selected ones of the teeth 56.

More particularly, each of the first-main first coils 90 preferablyincludes a plurality of interconnected first-main first loops includinga first-main innermost first loop 98, a first-main intermediate firstloop 100, and a first-main outermost first loop 102. The first-mainoutermost first loop 102 preferably at least substantially circumscribesthe first-main innermost first loop 98. The first-main intermediatefirst loop 100 is preferably positioned between the first-main innermostfirst loop 98 and the first-main outermost first loop 102.

Each first-main first loop 98, 100, and 102 preferably comprises aplurality of turns of the wire 50 a.

Each of the first-main innermost first loops 98 preferably includes apair of arcuately spaced apart, generally axially extending first-maininnermost first slot portions 104 extending through corresponding onesof the slots 58. Similarly, each of the first-main intermediate firstloops 100 preferably includes a pair of arcuately spaced apart,generally axially extending first-main intermediate first slot portions106 extending through corresponding ones of the slots 58. Likewise, eachof the first-main outermost first loops 102 preferably includes a pairof arcuately spaced apart, generally axially extending first-mainoutermost first slot portions 108 extending through corresponding onesof the slots 58.

Preferably, the first-main innermost, intermediate, and outermost firstslot portions 104, 106, and 108, respectively, all extend throughdifferent ones of the slots 58. More particularly, in a preferredembodiment, the first-main innermost, intermediate, and outermost firstloops 98, 100, and 102 of each of the first-main first coils 90 areconcentric and respectively circumscribe two (2), four (4), and six (6)of the teeth 56. For instance, in the preferred embodiment shownschematically in FIG. 4B and others, the first-main innermost first loop98 of a selected one of the first-main first coils 90 circumscribesteeth 36-1. The first-main intermediate first loop 100 of the same oneof the first-main first coils 90 circumscribes teeth 35-36-1-2. Thefirst-main outermost first loop 102 of the same one of the first-mainfirst coils 90 circumscribes teeth 34-35-36-1-2-3.

In a preferred embodiment, as shown in FIG. 4B, the locations of thepoles P when the first-main winding 50 is energized preferablycorrespond with respective ones of the first-main outermost first slotportions 108, such that the first-main outermost first slot portions 108are the first-main primary slot portions 96. That is, each of the pairsof first-main primary slot portions 96 defines a pair of arcuatelyspaced apart outermost margins of the corresponding first-main firstcoil 90.

In a preferred embodiment, each of the first-main second coils 92includes a pair of interconnected first-main second loops including afirst-main innermost second loop 110 and a first-main outermost secondloop 112. The first-main outermost second loop 112 preferably at leastsubstantially circumscribes the first-main innermost second loop 110.

Similar to the first-main first loops 98, 100, and 102 of the first-mainfirst coils 90, each first-main second loop 110 and 112 of thefirst-main second coils 92 preferably comprises a plurality of turns ofthe wire 50 a.

In a preferred embodiment, each of the first-main second coils 92includes a plurality of first-main second slot portions 114 eachextending through a corresponding one of the slots 58. Moreparticularly, each of the first-main innermost second loops 110preferably includes a pair of arcuately spaced apart, generally axiallyextending first-main innermost second slot portions 116 extendingthrough corresponding ones of the slots 58. Likewise, each of thefirst-main outermost second loops 112 preferably includes a pair ofarcuately spaced apart, generally axially extending first-main outermostsecond slot portions 118 extending through corresponding ones of theslots 58.

Preferably, the first-main innermost and outermost second slot portions116 and 118, respectively, all extend through different ones of theslots 58. More particularly, in a preferred embodiment, the first-maininnermost and outermost second loops 110 and 112 of each of thefirst-main second coils 92 are concentric and respectively circumscribetwo (2) and four (4) of the teeth 56. For instance, in the preferredembodiment shown schematically in FIG. 4B and others, the first-maininnermost second loop 110 of a selected one of the first-main secondcoils 92 circumscribes teeth 6-7. The first-main outermost second loop112 of the same one of the first-main second coils 92 circumscribesteeth 5-6-7-8.

Furthermore, the first-main primary slot portions 96 preferably extendthrough different ones of the slots 58 than any of the first-main secondslot portions 114 (i.e., the first-main innermost and outermost secondslot portions 116 and 118, respectively) such that the poles P arespaced from the first-main second slot portions 116 and 118 when thefirst-main winding 50 is energized.

Yet further, in keeping with the preferred arcuately alternatingarrangement of the first-main first and second coils 90 and 92,respectively, it is preferred that the first-main first slot portions 94(including the first-main innermost, intermediate, and outermost firstslot portions 104, 106, and 108, respectively) and the first-main secondslot portions 114 (including the first-main innermost and outermostsecond slot portions 116 and 118, respectively) all extend throughdifferent ones of the slots 58.

In a preferred embodiment, the second-main winding 52 is configuredsimilarly to the auxiliary winding 48 and the first-main winding 50.More particularly, as shown in FIGS. 4A-4C, the second-main winding 52is preferably configured identically to the auxiliary winding 48 exceptfor being rotated relative to the auxiliary winding 48 by ninety (90)electrical degrees and being positioned radially inwardly relative tothe auxiliary winding 48. The second-main winding is preferablyconfigured identically to the first-main winding 50 except for beingpositioned radially inwardly relative thereto.

Therefore, for the sake of brevity and clarity, redundant descriptions,particularly in regard to permissible variations of the windingconfigurations, will be generally avoided here. Unless otherwisespecified, the detailed descriptions of the auxiliary winding 48 and thefirst-main winding 50 should therefore be understood to apply at leastgenerally to the second-main winding 52, as well.

With particular reference to FIG. 4C, the second-main winding 52preferably includes a plurality of second-main first coils 120 woundabout the stator core 46 and a plurality of second-main second coils 122wound about the stator core 46. The second-main second coils 122 arepreferably alternately arcuately arranged with the second-main firstcoils 120.

The second-main winding 52 preferably includes three (3) of thesecond-main first coils 120 and three (3) of the second-main secondcoils 122.

In a preferred embodiment, each of the second-main first coils 120includes a plurality of second-main first slot portions 124 eachextending through a corresponding one of the slots 58.

The second-main first slot portions 124 of each of the second-main firstcoils 120 preferably include a pair of arcuately spaced apart, generallyaxially extending second-main primary slot portions 126. The location ofeach pole P preferably coincides with a corresponding one of thesecond-main primary slot portions 126 when the second-main winding 52 isenergized, such that the second-main winding 52 is a full pitch winding.That is, the poles P are located at selected ones of the slots 58 ratherthan, for instance, on selected ones of the teeth 56.

More particularly, each of the second-main first coils 120 preferablyincludes a plurality of interconnected second-main first loops includinga second-main innermost first loop 128, a second-main intermediate firstloop 130, and a second-main outermost first loop 132. The second-mainoutermost first loop 132 preferably at least substantially circumscribesthe second-main innermost first loop 128. The second-main intermediatefirst loop 130 is preferably positioned between the second-maininnermost first loop 128 and the second-main outermost first loop 132.

Each second-main first loop 128, 130, and 132 preferably comprises aplurality of turns of the wire 52 a.

Each of the second-main innermost first loops 128 preferably includes apair of arcuately spaced apart, generally axially extending second-maininnermost first slot portions 134 extending through corresponding onesof the slots 58. Similarly, each of the second-main intermediate firstloops 130 preferably includes a pair of arcuately spaced apart,generally axially extending second-main intermediate first slot portions136 extending through corresponding ones of the slots 58. Likewise, eachof the second-main outermost first loops 132 preferably includes a pairof arcuately spaced apart, generally axially extending second-mainoutermost first slot portions 138 extending through corresponding onesof the slots 58.

Preferably, the second-main innermost, intermediate, and outermost firstslot portions 134, 136, and 138, respectively, all extend throughdifferent ones of the slots 58. More particularly, in a preferredembodiment, the second-main innermost, intermediate, and outermost firstloops 128, 130, and 132 of each of the second-main first coils 120 areconcentric and respectively circumscribe two (2), four (4), and six (6)of the teeth 56. For instance, in the preferred embodiment shownschematically in FIG. 4C and others, the second-main innermost firstloop 128 of a selected one of the second-main first coils 120circumscribes teeth 36-1. The second-main intermediate first loop 130 ofthe same one of the second-main first coils 120 circumscribes teeth35-36-1-2. The second-main outermost first loop 132 of the same one ofthe second-main first coils 120 circumscribes teeth 34-35-36-1-2-3.

In a preferred embodiment, as shown in FIG. 4C, the locations of thepoles P when the second-main winding 52 is energized preferablycorrespond with respective ones of the second-main outermost first slotportions 138, such that the second-main outermost first slot portions138 are the second-main primary slot portions 126. That is, each of thepairs of second-main primary slot portions 126 defines a pair ofarcuately spaced apart outermost margins of the correspondingsecond-main first coil 120.

In a preferred embodiment, each of the second-main second coils 122includes a pair of interconnected second-main second loops including asecond-main innermost second loop 140 and a second-main outermost secondloop 142. The second-main outermost second loop 142 preferably at leastsubstantially circumscribes the second-main innermost second loop 140.

Similar to the second-main first loops 128, 130, and 132 of thesecond-main first coils 120, each second-main second loop 140 and 142 ofthe second-main second coils 122 preferably comprises a plurality ofturns of the wire 52 a.

In a preferred embodiment, each of the second-main second coils 122includes a plurality of second-main second slot portions 144 eachextending through a corresponding one of the slots 58. Moreparticularly, each of the second-main innermost second loops 140preferably includes a pair of arcuately spaced apart, generally axiallyextending second-main innermost second slot portions 146 extendingthrough corresponding ones of the slots 58. Likewise, each of thesecond-main outermost second loops 142 preferably includes a pair ofarcuately spaced apart, generally axially extending second-mainoutermost second slot portions 148 extending through corresponding onesof the slots 58.

Preferably, the second-main innermost and outermost second slot portions146 and 148, respectively, all extend through different ones of theslots 58. More particularly, in a preferred embodiment, the second-maininnermost and outermost second loops 140 and 142 of each of thesecond-main second coils 122 are concentric and respectivelycircumscribe two (2) and four (4) of the teeth 56. For instance, in thepreferred embodiment shown schematically in FIG. 4C and others, thesecond-main innermost second loop 140 of a selected one of thesecond-main second coils 122 circumscribes teeth 6-7. The second-mainoutermost second loop 142 of the same one of the second-main secondcoils 122 circumscribes teeth 5-6-7-8.

Furthermore, the second-main primary slot portions 126 preferably extendthrough different ones of the slots 58 than any of the second-mainsecond slot portions 144 (i.e., the second-main innermost and outermostsecond slot portions 146 and 148), such that the poles P are spaced fromthe second-main second slot portions 146 and 148 when the second-mainwinding 52 is energized.

Yet further, in keeping with the preferred arcuately alternatingarrangement of the second-main first and second coils 120 and 122,respectively, it is preferred that the second-main first slot portions124 (including the second-main innermost, intermediate, and outermostfirst slot portions 134, 136, and 138, respectively) and the second-mainsecond slot portions 144 (including the second-main innermost andoutermost second slot portions 146 and 148, respectively) all extendthrough different ones of the slots 58.

As noted previously, it is preferred that the auxiliary winding 48, thefirst-main winding 50, and the second-main winding 52 are each fullpitch windings. It is permissible according to some aspects of thepresent invention, however, for one or more of the windings to insteadbe a fractional pitch winding. Most preferably, though, the motorincludes at least one full pitch auxiliary winding and at least one fullpitch main winding.

Provision of exclusively full pitch auxiliary and main windings asdescribed preferably reduces winding harmonics to an almost negligiblelevel and, in turn, drastically reduces overall motor noise levels. Incontrast to conventional means of reducing noise (e.g., expanding theair gap between the rotor and the stator while continuing to provideconventional fractional pitch windings), which dampen the windingharmonics but do not address the source of the noise, the full pitchcoil layout described herein preferably reduces the source of theproblem and results in a motor that is not only quieter but is also moreresilient to mechanical variation. Such a solution is particularlyadvantageous in blower motor applications.

Although the above description presents features of preferredembodiments of the present invention, other preferred embodiments mayalso be created in keeping with the principles of the invention.Furthermore, these other preferred embodiments may in some instances berealized through a combination of features compatible for use togetherdespite having been presented independently in the above description.

The preferred forms of the invention described above are to be used asillustration only and should not be utilized in a limiting sense ininterpreting the scope of the present invention. Obvious modificationsto the exemplary embodiments, as hereinabove set forth, could be readilymade by those skilled in the art without departing from the spirit ofthe present invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention set forth in thefollowing claims.

What is claimed is:
 1. A blower motor for use in a machine, said motorcomprising: a stator; and a rotor rotatable about an axis, said statorincluding— a generally toroidal core including a plurality of arcuatelyspaced apart teeth, each pair of adjacent teeth defining a slottherebetween, and a first-main winding, said first-main windingincluding a plurality of first-main first coils wound about the core,each of said first-main first coils including a pair of arcuately spacedapart, generally axially extending first-main primary slot portions,each of said pairs of first-main primary slot portions defining a pairof arcuately spaced apart outermost margins of the correspondingfirst-main first coil, said first-main winding generating a plurality offirst-main poles at respective arcuately spaced apart first-main polelocations, said motor having a slot to pole ratio of 6 to 1, said slotsincluding a plurality of first-main pole-location slots, said first-mainwinding being a full pitch winding, with corresponding pairs of saidfirst-main primary slot portions and said first-main pole locationsbeing positioned within respective ones of the first-main pole-locationslots.
 2. The motor as claimed in claim 1, said first-main windingfurther including a plurality of first-main second coils wound about thecore, said first-main second coils being alternately arcuately arrangedwith the first-main first coils, each of said first-main second coilsincluding a plurality of arcuately spaced apart, generally axiallyextending first-main second slot portions, each of said first-mainsecond slot portions extending through a corresponding one of the slots.3. The motor as claimed in claim 2, said first-main primary slotportions extending through different ones of the slots than any of thefirst-main second slot portions, such that the first-main pole locationsare spaced from the first-main second slot portions.
 4. The motor asclaimed in claim 3, each of said first-main first coils comprising aplurality of interconnected first-main first loops including afirst-main innermost first loop, a first-main outermost first loop atleast substantially circumscribing the first-main innermost first loop,and a first-main intermediate loop positioned between the first-maininnermost first loop and the first-main outermost first loop, each ofsaid first-main innermost first loops including a pair of arcuatelyspaced apart, generally axially extending first-main innermost firstslot portions, each of said first-main intermediate first loopsincluding a pair of arcuately spaced apart, generally axially extendingfirst-main intermediate first slot portions, each of said first-maininnermost and intermediate first slot portions extending through acorresponding one of the slots, each of said first-main outermost firstloops presenting the first-main primary slot portions for thatfirst-main first coil.
 5. The motor as claimed in claim 4, saidfirst-main innermost, intermediate, and outermost first loops of each ofthe first-main first coils respectively circumscribing two, four, andsix of the teeth.
 6. The motor as claimed in claim 4, said motorincluding a first-main wire forming the first-main winding, saidfirst-main innermost, intermediate, and outermost first loops of each ofthe first-main first coils each comprising a plurality of turns of thefirst-main wire.
 7. The motor as claimed in claim 4, each of saidfirst-main second coils comprising a pair of interconnected first-mainsecond loops including a first-main innermost second loop and afirst-main outermost second loop at least substantially circumscribingthe first-main innermost second loop, each of said first-main innermostsecond loops including a pair of arcuately spaced apart, generallyaxially extending first-main innermost second slot portions, each ofsaid first-main outermost second loops including a pair of arcuatelyspaced apart, generally axially extending first-main outermost secondslot portions, each of said first-main innermost and outermost secondslot portions extending through a corresponding one of the slots.
 8. Themotor as claimed in claim 7, said first-main innermost and outermostsecond loops of each of the first-main second coils respectivelycircumscribing two and four of the teeth.
 9. The motor as claimed inclaim 1, said stator further including an auxiliary winding forinitiating rotor rotation, said auxiliary winding being electrically outof phase with the first-main winding.
 10. The motor as claimed in claim9, said auxiliary winding including a plurality of auxiliary first coilswound about the core, each of said auxiliary first coils including apair of arcuately spaced apart, generally axially extending auxiliaryprimary slot portions, each of said pairs of auxiliary primary slotportions defining a pair of arcuately spaced apart outermost margins ofthe corresponding auxiliary first coil, said auxiliary windinggenerating a plurality of auxiliary poles at respective arcuately spacedapart auxiliary pole locations, said slots including a plurality ofauxiliary pole-location slots, said auxiliary winding being a full pitchwinding, with corresponding pairs of said auxiliary primary slotportions and said auxiliary pole locations being positioned withinrespective ones of the auxiliary pole-location slots.
 11. The motor asclaimed in claim 10, said auxiliary winding further including aplurality of auxiliary second coils wound about the core, said auxiliarysecond coils being alternately arcuately arranged with the auxiliaryfirst coils, each of said auxiliary second coils including a pluralityof arcuately spaced apart, generally axially extending auxiliary secondslot portions, each of said auxiliary second slot portions extendingthrough a corresponding one of the slots.
 12. The motor as claimed inclaim 11, said auxiliary primary slot portions extending throughdifferent ones of the slots than any of the auxiliary second slotportions, such that the auxiliary pole locations are spaced from theauxiliary second slot portions.
 13. The motor as claimed in claim 12,each of said auxiliary first coils comprising a plurality ofinterconnected auxiliary first loops including an auxiliary innermostfirst loop, an auxiliary outermost first loop at least substantiallycircumscribing the auxiliary innermost first loop, and an auxiliaryintermediate first loop positioned between the auxiliary innermost firstloop and the auxiliary outermost first loop, each of said auxiliaryinnermost first loops including a pair of arcuately spaced apart,generally axially extending auxiliary innermost first slot portions,each of said auxiliary intermediate first loops including a pair ofarcuately spaced apart, generally axially extending auxiliaryintermediate first slot portions, each of said auxiliary innermost andintermediate first slot portions extending through a corresponding oneof the slots, each of said auxiliary outermost first loops presentingthe auxiliary primary slot portions for that auxiliary first coil. 14.The motor as claimed in claim 13, said auxiliary innermost,intermediate, and outermost first loops of each of the auxiliary firstcoils respectively circumscribing two, four, and six of the teeth. 15.The motor as claimed in claim 13, said motor including an auxiliary wireforming the auxiliary winding, said auxiliary innermost, intermediate,and outermost first loops of each of the auxiliary first coils eachcomprising a plurality of turns of the auxiliary wire.
 16. The motor asclaimed in claim 13, said auxiliary winding including a plurality ofauxiliary second coils wound about the core, said auxiliary second coilsbeing alternately arcuately arranged with the auxiliary first coils,each of said auxiliary second coils comprising a pair of interconnectedauxiliary second loops including an auxiliary innermost second loop andan auxiliary outermost second loop at least substantially circumscribingthe auxiliary innermost second loop, each of said auxiliary innermostsecond loops including a pair of arcuately spaced apart, generallyaxially extending auxiliary innermost second slot portions, each of saidauxiliary outermost second loops including a pair of arcuately spacedapart, generally axially extending auxiliary outermost second slotportions, each of said auxiliary innermost and outermost second slotportions extending through a corresponding one of the slots.
 17. Themotor as claimed in claim 16, said auxiliary innermost and outermostsecond loops of each of the auxiliary second coils respectivelycircumscribing two and four of the teeth.
 18. The motor as claimed inclaim 10, said stator further including a second-main winding that iselectrically in phase with the first-main winding, said second-mainwinding including a plurality of second-main first coils wound about thecore, each of said second-main first coils including a pair of arcuatelyspaced apart, generally axially extending second-main primary slotportions, each of said pairs of second-main primary slot portionsdefining a pair of arcuately spaced apart outermost margins of thecorresponding second-main first coil, said second-main windinggenerating a plurality of second-main poles at respective arcuatelyspaced apart second-main pole locations, said slots including aplurality of second-main pole-location slots, said second-main windingbeing a full pitch winding, with corresponding pairs of said second-mainprimary slot portions and said second-main pole locations beingpositioned within respective ones of the second-main pole-locationslots.
 19. The motor as claimed in claim 9, said auxiliary winding being90 electrical degrees out of phase with the first-main winding.
 20. Themotor as claimed in claim 1, said motor having 36 slots and 6 poles.